Motor-driven rotary toothbrush with reversing gear



July 7, 1964 J. R. ALBRIGHT MOTOR-DRIVEN ROTARY TOOTHBRUSH WITH REVERSING GEAR Filed June 17, 1965 INVENTOR United States Patent ice 3,139,639 MOTOR-DRIVEN ROTARY TOOTHBRUSH WITH REVERSING GEAR John Reuben Albright, 2620 La Cuesta Drive, Hollywood 46, Calif. Filed June 17, 1963, Ser. No. 288,285 9 Claims. (CI. 15-23) This invention relates to an electric motor-driven rotary toothbrush device of a portable type having its driving motor embodied in the handle thereof, and has as its general object to provide, in such a toothbrush device, a reversing gear shift, easily operable by the hand in which the device is held, for reversing the direction of rotation of the brush.

In the cleaning of teeth, it is common practice to brush downwardly on the surfaces of the upper teeth and to brush upwardly on the surfaces of the lower teeth, so as to drive the clinging particles of food away from the gums, to massage the gums toward the tips of the teeth, and to avoid pushing the gums back along the roots of the teeth. Where a unidirectional rotary toothbrush is employed, it is necessary to reverse the device end-to-end in order to effect a reversed direction of brushing against the teeth. This becomes awkward and time-consuming. The present invention is directed principally to this problem and embraces the following objects:

(1) To provide an improved rotary toothbrush embodying a reversing gear for reversing the brush direction without shifting the hand-held position of the device.

(2) To provide such reversing gear which is instantaneously operable.

(3) To provide an improved rotary toothbrush having reversing gearing in arrangement wherein gear-shifting is accomplished by bodily tilting the drive motor about a transverse pivotal connection of the motor to the case, the shiftable gear element being a drive pinion on the end of the motor shaft.

(4) To provide such a reversing gear having three positions, namely, neutral, forward and reverse.

(5) To provide such a reversing gear in connection with an actuator which is operable by a sliding button engageable by the thumb of the user.

(6) To provide such a reversing gear having means for yieldingly holding the shiftable gear element in its alternative forward and reverse drive positions.

Other objects and advantages will become apparent in the ensuing specification and appended drawing in which:

FIG. 1 is a side elevational view of a reversible rotary toothbrush embodying my invention, with the case and other parts thereof shown in longitudinal section;

FIG. 2 is a transverse sectional view of the same taken on the line 22 of FIG. 1;

FIG. 3 is a transverse sectional View of the same taken on the line 3-3 of FIG. 1;

FIG. 4 is a transverse sectional View of the same taken on the line 44 of FIG. 1;

FIG. 5 is a transverse sectional View of the same taken on the line 55 of FIG. 1;

FIG. 6 is a front end view of the same with the brush and guard elements removed;

FIG. 7 is a cross-sectional view taken on line 77 of FIG. 1; and

FIG. 8 is a cross-sectional view taken on line 88 of FIG. 1.

Referring now to the drawings in detail, I have shown therein, as an example of one form in which the invention may be embodied, a rotary toothbrush comprising, in general, an elongated cylindrical tubular case A, an elongated electric drive motor B therein, a reversible spur gear transmission C in one end of the case, a gear shift actuator and linkage D adjacent the transmission C, a rotary 3,139,639 Patented July 7, 1964 brush element E detachably connected to a shaft driven through the gearing C, and a guard element F detachably mounted to the adjacent end of the case A. In the normal use of the device, the brush and guard elements F will be detached for cleaning and sterilizing after each use of the device.

Case A comprises a cylindrical barrel 10, a rear end member 11 which may be in the form of a removable cap as indicated, and a forward end fitting 12 which likewise may be in the form of a removable cap. Fitting 12 terminates in an axially extending boss 13 having a cylindrical bearing-mounting bore and having on one side thereof a socket 14 for detachable mounting of the shank of guard F. As shown in FIG. 6, socket 14 is preferably of arcuate, segmental cylindrical cross section.

In one side of the case barrel 10, near its forward end, is a longitudinally extending actuator guide 16 of shallow channel section (FIG. 3). Near its rear end barrel 10 may be provided with a slot 17 for a switch-actuator lever.

Motor B is a small fractional horsepower electric motor of an elongated, small-diameter type including a body portion 21, a projecting shaft-bearing neck 22 at its forward end, and an electrical terminal or connector unit 23 at its rear end, which may embody an on-off switch having a suitable actuator lever 24 extending through slot 17 in barrel 10 for manual control. A suitable service cord connection 25 may be mounted upon the rear end cap 11 and electrically connected to the motor through the connector unit 23 by a conductor cord 26.

The rear end of the motor body 21 is pivotally attached to the case A by suitable trunnions or pivot pins 27 and bearing bosses 28 on the motor body 21 and/or case barrel 10 (FIG. 2).

Motor 21 has a drive shaft 29 extending through the bearing neck 22 and provided with a drive pinion 30 secured to its forward end.

Reversing Gear Unit C comprises a pair of drive-receiving gears 35, 36 mounted upon respective counter shafts 37 which are journalled in suitable bearing brackets 38, 33 in the forward end of barrel 10. Gear 36 is a forward-drive gear. Gear 35 is a reverse-drive gear, and is in constant mesh with a reversing gear 35' rotatably mounted on a countershaft carried by bracket 33. Each of the gears 35, 36 constitutes one of a pair of gears in a cluster which in each instance includes a pinion 39 constantly in mesh with a driven gear 40 which is secured on a driven shaft 41. Shaft 41 is journalled in suitable antifriction bearing means such as indicated at 42, 43, mounted in the bearing boss 13. The shaft 41 has an end portion projecting from the boss 13 and provided with a suitable keyway 44 or equivalent means for establishing .a detachable driving connection to the brush unit E.

At this point it may be noted that the motor-mounting pivots 27, 28 provide for tilting the motor B to opposite sides of a neutral position shown in full lines, around a transverse diametral pivot axis near its rear end whereby the drive pinion 30 may be shifted from a neutral, intermediate position shown in full lines in FIG. 1 to a position meshing electively with the forward drive gear 36 or the reversing gear 35', as indicated by the phantom positions of the drive pinion 30 shown in FIG. 8.

Actuator Mechanism D comprises an actuator slide 50 mounted for axial sliding movement in the slide channel 16 of the case, an actuator button 51 inopposed relation to the slide 50 externally of the case A, and a narrowed web 52 integrally connecting the slide 50 to the button 51 and slidable in a longitudinal slot 53 in the slide channel 16.

Actuator mechanism D further includes toggle linkage connecting the slide 50 to the motor neck 22, such linkage comprising a link 55 having one end connected by a pivot 3 56 to a clevise 57 (FIG. 3) on the inner side of slide 50, and having at its other end a fork 58 which embraces the motor neck 22 and is connected thereto on a transverse, diametral pivot axis by a pair of pivots 59.

The toggle link 55 extends in a diagonal direction between the pivots 56 and 59. By shifting the actuator button 51 toward the rear end of the case A (leftward as viewed in FIG. 1) the motor B will be tilted toward the actuator button 51 and the drive pinion 30 will be shifted into mesh with the reverse drive gear 35'. By shifting the button 51 toward the forward end of the case A, the toggle action of the link 55 will shift the motor B in the opposite direction, bringing the drive pinion into mesh with the forward drive gear 36. In a neutral position midway between the two limit positions of button 51 in the shifts just described, the axis of motor B will be parallel to the axis of case A and the drive pinion 30 will be in a neutral position disengaged from both of the gears 35, 36.

The motor B is latched in each of its three positions by spring latch means comprising (FIGS. 1 and 4) a pair of spring latch arms 61 disposed in laterally spaced, parallel positions on opposite sides of a diameter of the barrel 10, with their ends suitably secured thereto as indicated at 62. The intermediate portions of latch arms 61 are provided with respective detents 63, 64 and 65, in the form of V-shaped corrugations. Embraced between the detents 6365 is a cooperating latch tip 66 which may be formed as an integral extension of the motor bearing neck 22 and which has diametrically opposed latch projections 67 of obtuse wedge shape adapted to bottom in the respective detents 63, 64, 65.

In order to effect rapid shift from forward to reverse rotation, and vice versa, the invention provides for braking the rotation of the motor shaft 29 and pinion 30 in the neutral gear-shift position. To this end, the latch arms 61 are provided, midway between their ends, with parallel, diametrically opposed brake shoes 71 which may be formed integrally with the respective arms 61 and which project on opposite sides of the axis of driven shaft 41, parallel thereto, in embracing yielding contact with the brake drum 72 when the latter is in the intermediate position as shown in FIG. 5. The brake shoes 71 preferably include arcuate intermediate portions 73, shaped for mating engagement with the periphery of brake drum 72, and flared extremities 74 for leading the drum 72 into the restricted space defined between the shoes 71 when the drum is being shifted back to the neutral position from either of the drive positions which are indicated in phantom in FIG. 6. The latch arms 61 and shoes 71 are preformed and positioned so that the shoes 71 will be lightly spring-loaded against the opposite sides of the periphery of drum 72 when the latter is in the neutral position, and correspondingly, when the motor, drive pinion, drum assembly is shifted to either of the drive positions, the shoes 71 will be slightly closer to one another than in their positions engaged against the drum (but still out of contact with the drum 72 in the respective drive position).

As the drum 72 moves into the neutral position, it will engage the flared extremities 74 of the shoes and will operate thereon with a camming action to spread the shoes until it is received between them. The yielding of the shoes 71 is accommodated by torsional spring action in the arms 61, and the light yielding spring-loading of the shoes 71 against the drum 72 is effected by such torsional spring action, in which the detents 63-65 are not required to undergo any appreciable spreading movements, such as would interfere with their detent action.

Brush E comprises a shank 81 having at one end a socket 82 to receive the projecting end of drive shaft 41 and having a suitable key element (not shown) for mating engagement in the keyway 44. Brush bristles 83 are anchored in the opposite end of the shank 81.

Guard F comprises a shank 86 of transversely arched Cross section for snug socketing engagement in the socket 14, and a somewhat wider hood 87 which is of segmentalcylindrical form such as to cover roughly /a the circumference of the brush 83 and to thereby protect the labial membranes in the mouth against injury from the brush- In the operation of the device, after the motor has been turned on by actuating the switch 23 the user may grasp the case A in his hand with his thumb engaged against the actuator button 51 and his fingers encircling the case circumferentially adjacent the button. Keeping his thumb on the button 51 he then inserts the brush unit E and the associated guard F into the mouth, and, utilizing the case as a handle, can rotate the device about its longitudinal axis to the proper position to engage the brush bristles against the teeth. With the brush rotating in one direction, he can then clean the upper teeth. When it is desired to clean the lower teeth, the device is tilted to bring the brush opposite the lower teeth and simultaneously the button 51 is shifted to the opposite drive position. The shifting is accomplished sufficiently slowly so that as the motor-drive gear assembly passes through the intermediate position, the brake shoes 71 will engage the periphery of brake drum 72 and arrest the rotation of the motor, and the shifting is then completed to the reversed position, in which braking will be released and the motor will be permitted to resume operation, driving the brush in the reverse direction. Braking action will continue while the brake drum 72 is being withdrawn from between the brake shoes 71, final braking action being effected by engagement of the brake shoe tips 74 against the drum 72 while the drive gear 30 is establishing meshing engagement with one of the gears 35, 36. Release of braking engagement of the tips 74 against the drum 72 is effected substantially at the point where full meshing engagement is established between the teeth of drive gear 30 and gears 35, 36.

I claim:

1. A motor-driven rotary toothbrush comprising, in combination: an elongated case; a motor; a drive shaft projecting from one end of said motor; pivot means mounting said motor within said case near one end of the case and at a distance from said end of the motor for tilting movements on an axis transverse to the axis of said shaft; a drive pinion on said shaft; a driven shaft aligned with said drive shaft and projecting from the other end of the case; a rotary brush coupled to said driven shaft; reversible gearing comprising a forward drive pinion and a reversing pinion on opposite sides of said drive pinion, normally in radially opposed, spaced relation thereto and selectively engageable by tilting said motor in opposite directions about said transverse axis, and gearing for transmitting drives from said forward drive and reversing pinions respectively to said driven shaft; and actuator means for tilting said motor.

2. A motor-driven rotary toothbrush comprising, in combination: an elongated case; an elongated motor; a drive shaft projecting from one end of said motor; pivot means mounting the other end of said motor within the case for tilting movements on an axis transverse to the axis of said shaft; a drive pinion on said shaft; a driven shaft aligned with said drive shaft and projecting from the end of the case; a rotary brush coupled to said driven shaft; reversible gearing comprising a driven gear on the inner end of said driven shaft, a pair of countershafts each geared to said driven gear at one end and having a drive-receiving pinion at its other end, in radially-opposed relation to said drive pinion, and a reversing gear in mesh with one of said drive-receiving pinions, the other drivereceiving pinion and said reversing gear each being selectively engageable by said drive pinion upon tilting said motor in one direction about said transverse axis; and actuator means acting between said one end of the motor and said case for tilting said motor.

wall of said case for sliding movement longitudinally of the case; and a toggle link pivotally connected at one end to said slide and at its other end to said motor, said link extending diagonally so as to resolve said longitudinal movement to transverse movement of the movable end of the case.

4. A toothbrush as defined in claim 3, including detent means for yieldingly holding said motor in each of its positions of adjustment.

5. A toothbrush as defined in claim 4, wherein said motor has an elongated bearing neck through which said drive shaft extends, and wherein said detent means comprises a pair of spaced, parallel resilient latch arms embracing said neck and in yielding engagement therewith, said arms having detent depressions in which opposite sides of said neck make latching engagement.

6. A toothbrush as defined in claim 1, wherein said motor has a neutral position in which said drive pinion is out of mesh with both of said opposed gears, and including a brake drum on said drive shaft and a springmounted brake shoe positioned to engage said brake drum to brake said motor in the neutral position thereof.

7. A toothbrush as defined in claim 1, wherein said motor has a neutral position in which said drive pinion is out of mesh with both of said opposed gears, and including a brake drum on said drive shaft and a pair of spaced, parallel spring arms having respective brake shoes yieldingly embracing said drum and operative to arrest the rotation of said motor in the neutral position thereof.

8. A toothbrush as defined in claim 1, wherein said motor has a neutral position in which said drive pinion is out of mesh with both of said opposed gears, and including a brake drum on said drive shaft and a pair of spaced, parallel spring arms having respective brake shoes yieldingly embracing said drum and operative to arrest the rotation of said motor in the neutral position thereof, said motor having'a neck projecting between said spring arms and said spring arms having detent means engageable with opposite sides of said neck to latch said motor in selected positions of adjustment.

9. A toothbrush as defined in claim 1, wherein said case has a socket extending in parallel, adjacent relation to said driven shaft, and a guard having a shank receivable in said socket and a guard hood positioned for covering one side of said brush.

References Qited in the file of this patent UNITED STATES PATENTS 2,185,229 Scott Jan. 2, 1940 2,468,453 Mallentjer Apr. 26, 1949 2,618,161 Mason Nov. 18, 1952 FOREIGN PATENTS 333,005 France Nov. 13, 1903 

1. A MOTOR-DRIVEN ROTARY TOOTHBRUSH COMPRISING, IN COMBINATION: AN ELONGATED CASE; A MOTOR; A DRIVE SHAFT PROJECTING FROM ONE END OF SAID MOTOR; PIVOT MEANS MOUNTING SAID MOTOR WITHIN SAID CASE NEAR ONE END OF THE CASE AND AT A DISTANCE FROM SAID END OF THE MOTOR FOR TILTING MOVEMENTS ON AN AXIS TRANSVERSE TO THE AXIS OF SAID SHAFT; A DRIVE PINION ON SAID SHAFT; A DRIVEN SHAFT ALIGNED WITH SAID DRIVE SHAFT AND PROJECTING FROM THE OTHER END OF THE CASE; A ROTARY BRUSH COUPLED TO SAID DRIVEN SHAFT; REVERSIBLE GEARING COMPRISING A FORWARD DRIVE PINION AND A REVERSING PINION ON OPPOSITE SIDES OF SAID DRIVE PINION, NORMALLY IN RADIALLY OPPOSED, SPACED RELATION THERETO AND SELECTIVELY ENGAGEABLE BY TILTING SAID MOTOR IN OPPOSITE DIRECTIONS ABOUT SAID TRANSVERSE AXIS, AND GEARING FOR TRANSMITTING DRIVES FROM SAID FORWARD DRIVE AND REVERSING PINIONS RESPECTIVELY TO SAID DRIVEN SHAFT; AND ACTUATOR MEANS FOR TILTING SAID MOTOR. 